Kissimmee Police officer Matthew Baxter was shot and killed in the Florida town on an unusually violent night. Photo: Kissimmee Police Department
Six US police officers were shot in one night in the states of Florida and Pennsylvania, one fatally, prompting President Donald Trump to tweet his support for the slain officer's department early on Saturday.
My thoughts and prayers are with the @KissimmeePolice and their loved ones. We are with you!#LESM
In the central Florida city of Kissimmee - close to the Walt Disney World Resort and other amusement parks - Officer Matthew Baxter was killed and Sergeant Sam Howard was left in "grave critical condition and the prognosis does not look good," police chief Jeff O'Dell said at a news conference early on Saturday.
Authorities in Florida said a suspect has been arrested in the fatal shooting of a police officer and the grave wounding of another officer.
Kissimmee Police Chief Jeff O'Dell said on Saturday that Everett Miller was arrested several hours after the shootings late Friday in this city south of Orlando.
He faces a first-degree murder charge.
Authorities originally said they believed there were four suspects, but the chief said no other arrests are anticipated.
The officers had been checking on suspicious people in an area known for drug activity around 11.30am AEDT on Friday night. Five minutes later, authorities received a call that police officers had been shot.
First responders found the police officers "gravely wounded" in the road, Mr O'Dell said. "My thoughts and prayers are with the @KissimmeePolice and their loved ones. We are with you!" Mr Trump, a staunch supporter of US law enforcement, tweeted early on Saturday.
In the northern Florida city of Jacksonville, sheriff's officers responding to an attempted suicide call late Friday were confronted by a suspect firing a high-powered rifle, Director Mike Bruno told a news conference.
Two officers were shot in the exchange of gunfire, one hit in both hands and the other in the stomach, Mr Bruno said. The suspect was killed.
And two Pennsylvania state troopers were shot Friday night, the agency said. "Two state troopers shot and [the] suspect is deceased," Pennsylvania State Police spokeswoman Melinda Bondarenka told ABC News. "We are not releasing any more details at this time."
Both troopers are expected to survive, ABC said of the shooting in the community of Fairchance, about 97 kilometres south of Pittsburgh.